Cardiac Transplantation: Anesthetic Management

ANESTHETIC MANAGEMENT

Proper timing and coordination are necessary between the donor organ retrieval team and the transplant center. Premature induction of anesthesia unnecessarily prolongs the time under anesthesia for the recipient, whereas delayed induction may jeopardize graft function by prolonging the period of ischemia.

Patients may receive little advance warning of the availability of a suitable organ. Many—if not most—will have eaten a recent meal and should be considered to have a full stomach. Oral cyclospo-rine must be given preoperatively. Administration of a clear antacid (sodium citrate), a histamine H₂-receptor blocker, and metoclopramide should be considered. Any sedating premedication may be administered intravenously just prior to induction.

Monitoring is similar to that used for other cardiac procedures and is often established prior to induction. Strict asepsis should be observed dur-ing invasive procedures. Use of the right internal jugular vein for central access does not appear to compromise its future use for postoperative endo-myocardial biopsies. A pulmonary artery catheter is used in many centers for postbypass manage-ment. It need not be placed in the pulmonary artery before CPB.

A rapid sequence induction may be performed. The principal objective of anesthetic management is to maintain organ perfusion until the patient is on CPB. Induction may be carried out with small doses of opioids (fentanyl, 5–10 mcg/kg) with or without etomidate (0.2–0.3 mg/kg). A low-dose ketamine– midazolam technique (above) may also be suitable. Sufentanil, 5 mcg/kg, followed by succinylcholine, 1.5 mg/kg, can be used as a rapid-sequence tech-nique. Anesthesia is maintained in a similar fash-ion as for other cardiac operations. A TEE probe is placed following induction, and antirejection drugs are given.

Sternotomy and cannulation for CPB may be complicated by scarring from prior cardiac opera-tions. Aminocaproic acid or tranexamic acid can be used to decrease postoperative bleeding. CPB is initiated following cannulation of the aorta and both cavae. If a pulmonary artery catheter was placed, it must be completely withdrawn from the heart with its tip in the superior vena cava. It must remain within its sterile, protective sheath if it is to be safely refloated again into the pulmonary artery following CPB. The recipient’s heart is then excised, allowing the posterior wall of both atria (with the caval and pulmonary vein openings) to remain. The atria of the donor heart are anasto-mosed to the recipient’s atrial remnants (left side first). The aorta and then the pulmonary artery are anastomosed end to end. The donor heart is then flushed with saline and intracardiac air is evacu-ated. Methylprednisolone is given before the aortic cross-clamp is released.

Inotropic support is usually started prior to separation from CPB to counteract bradycar-dia from sympathetic denervation. Prolonged graft ischemia may result in transient myocardial depression. Slow junctional rhythms are common and may require epicardial pacing. Although the transplanted heart is totally denervated and direct autonomic influences are absent, its response to circulating catecholamines is usually normal. The pulmonary artery catheter can be refloated into position after CPB and is used in conjunction with TEE to evaluate the patient. The most common post-CPB problem is right ventricular failure from pulmonary hypertension, which should be treated with hyperventilation, prostaglandin E₁ (0.025–0.2 mcg/kg/min), nitric oxide (10–60 ppm), and an RVAD, if necessary. Bleeding is a common problem because of extensive suture lines and preoperative hemostatic defects.

Patients will be extubated when they meet criteria, as with other major cardiac operations. The postoperative course may be complicated by acute rejection, renal and hepatic dysfunction, and infections.